Cyanide and method of controlling the porosity thereof



Patented Aug. 8, 1933 I '7 i 7 l I g UNITED sr s PATENT OFFICE it ,.1,92 1,299 v i it GYANIDE-AND METHOD OF CONTROLLING THE POROSITY THEREOF- -i Vartkes Migrdichian, Elizabeth, N. J.,'assig nor to American Cyan'amid Company, New York, N. Y., a Corporation of Maine No Drawing. Application March 12, 1929 Serial No. 346,501 V s Claims.- (01. 23-79) 1 This invention relates to a'method of prepar-i demonstrated that if a stratum of crude fuseding a cyanide such as crude calcium cyanide, cyanide is chilled quickly and throughout, a with any desired degree of porosity or density, much denser product, substantially free from and to the product thus produced, gas cavities, is produced, than if a state of 'plas 5 The patent to Walter s. Landis No. 1,359,257 tic fusion is maintained either by s w n up discloses a method of preparing crude calcium the rate of flow of cooling medium y thickcyanide by reacting together calcium cyanamid, ening the strata to be cooled. I common salt and calcium carbide, in an electric There is a Considerable difference in the p furnace. The product, to wit: principally cale' v y 0 the dense and p r Cyanide.

cium cyanide with minor amounts of sodium produced according to this invention, and it has chloride, calcium oxide, graphite, calcium cyana-- b possible to produce a Crude Calcium ymide and other impurities, is produced almost nid s above outlined in flakes less than continuously as a result of this reaction in a in thickness in Which the p fic gravity fused condition and this fused salt is then cooled Was greater an 1.7 03. Flakes 0.030" in 15. t b l 400 (3, thickness have been produced in which the spe- 0 A suitable apparatus for cooling the same is eifie g v y Was as high as 50 that y shown and described in the patent to George E. regulating the pro as h r in described a Cox No. 1,649,511 which consists essentially of a y n y be p d ov a W r nse of cooling or chilling wheel which takes the fused p fi gravitiescrude cyanide from the production furnace in Crude Calcium Cyanide Specifically has a u 75 strata of varying thicknesses upon its cooled her of y important u es in whic t is deperiphery so as to produce lumps or fl k upon sirable to use a porous product. One of these chilling. uses is the generation of hydrocyanic acid gas The present invention is based primarily upon therefrom by the action thereon of moist air.

the discovery that the degree of density or y, the more D the P t the porosity of the resultant product may be greater the ease of hydrocyanic acid evolution. trolled by the rate of cooling or chilling of the My p m ts hav u v yv d mo s at d fused product, and this is dependent u th that utilizing a uniform rateof flow of moist rate at which the cooling medium is supplied, or granules of Calcium cyanide p p the thickness of the strata being chilled, or both. from flakes of Certain thickness Produce A microscopic examination of calcium cyanide r r generation f hy r y ni id a h n prepared as above outlined discloses the fact r n l of the same i produced fr m cy that the thicker the strata being chilled or the de Of a lesser thiekness- Where Substantially slower the rate of cooling, the greater the nume Same Cooling procedure Obtained- Co se- 35 ber of gas pockets that will exist in the finished q y. y prolonging the cooling p it r product. Obviously, an apparatus adjusted to y decreasing the rate of 0 of Cooling deliver a certain quantity of cooling medium to d u y increasing the thickness o e fused the chilling device will produce various rates of material d hence maintaining a p d Of cooling, dependent entirely upon the thickness plastic u a longer length of time, One

or the strata being cooled. Thus the rate. of may pr a hishdeer f por y.

cooling may be changed either by tr ting On the other hand, where a cyanide is to be thinner or thicker strata of moltenmaterial or usedother than for the generation, of y by adjusting the rate of flow of cooling medium. ey ni acid gas m t reaction wi h moist This change in porosity or density is probair, and a more stable product is desired, the

' -ably due to the fact that the fused material dence variety will be preferable. Thus, a prodwhile in that condition, undergoes a decomponot containing substantially no, or a minimum sition, so that a quantity of entrapped gas in quantity of, gas pockets of appreciable size, may

small or minute. bubbles is produced, and if the be shipped or exposed to the air' for long pe i stratum is chilled quickly and substantially l'iods of time Without material decomposition,

these'minute bubbles do not have time to agspecific gravity than the porous variety likewise glomerate, or else do not format all, with the permits the packing ofa given quantity thereresult that the final solid material does not of in a materially less volume. contain gas pockets of any appreciable or ma- While'I have described the preparation of a 1 0 v 5 'terial size. At any rate, it has been clearly cyanide substantially free from gas cavities throughout its depth so as to set the cyanide, Thefact that such a product is of a greater 1 i throughout, yet obviously by so treating the molten product as to produce a substantial,

thickness or crust thereon free from gas pockets, this dense crust will of itself prevent undue decomposition of the interior of the flakes or lumps during shipment" or until: used.

Obviously, this discovery is equally applicable to cyanides other than calcium cyanide, and it is to be understood that the invention is consid-p ered to cover any like salt produced in a state" of fusion in which the cooling is; so. regulated and controlled as to determine the size and quantity of gas pockets in theresultant. product.

It may be desirable under some circumstances to convert a cyanide or other salt already produced into a porous or denser form, and this may be done by fusing the already: produced salt and continuing the treatment from that point.

It is impossible to state precisely the exact rate of cooling or thickness of strata desired as this. will be dependent upon the degree of porosity or density required. Obviously, with they disclosure that this may be varied at will by the rate of cooling or the thickness of strata, or both, anyone skilled in this art will be enabled to so regulate the process for himseli as to produce the results desired.

What I claim is: n r V 1. A dense crude calcium cyanide having a specific gravity greater than 1.7903.

2. A cyanide having a crust thereon substantially e r m s i ie -f 3. A method of preparing a porous; cyanide which includes the steps of producing the fused salt and then slowly cooling the same at such a rate that the resultant product contains gas 6. A porous flake cyanide containing gas. cavities of substantial size throughout.

VARTKES MIGRDICHIAN'.

in, the resultant product. 

